The neocortex is subdivided into areas of anatomical and functional specialization. But little is known about the specialization of neural activities among different neocortical areas. Neural activity in neocortex often becomes synchronous and oscillatory in relation to specific normal and abnormal behavioral states. Our recent work has revealed that the motor cortex contains a unique excitatory network that during a variety of conditions generates synchronous oscillatory activity in the alpha frequency 7-14 Hz range (~10 Hz oscillations). Moreover, this network is further suppressed in the adjacent somatosensory cortex, which does not generate these oscillations unless specific outward currents are blocked. The goal of this research project is to reveal the substrate responsible for the alpha resonance of neocortex, and to characterize its functional role during behavior. There are three specific aims: 1) To characterize ~10 Hz oscillations unmasked in somatosensory cortex by K+ channel blockers; 2) To determine the mechanisms that are unmasked to generate ~10 Hz oscillations in motor and somatosensory cortex; 3) To characterize rhythmic activity in motor and somatosensory cortex in behaving animals. We will employ a variety of methods using slices in vitro and behaving animals in vivo. The proposed experiments will reveal many aspects of the synaptic, cellular and network organization of the motor and somatosensory cortices. This information will be relevant to understanding the neural substrate underlying abnormal neural activities that produce tremor, cortical myoclonus and Jacksonian- type seizures. PUBLIC HEALTH RELEVACE These studies are directed at deciphering the neural substrate responsible for tremor, myoclonus and Jacksonian-type seizures, which are common symptoms of many neurological disorders.